http://www.mdpi.com/journal/marinedrugs/special_issues/halogen-metabolites/ Dear Colleagues, Halogenated secondary metabolites, while rare in terrestrial plants, are common in marine organisms due to the abundance of chloride and bromide ions in seawater. Marine biota produce a variety of halogen containing organic compounds that have 1-30 carbon atoms. Organisms that have the ability to form halogenated compounds have been found among various species of algae, bacteria, sponges, mollusks, coelenterates and several marine worms. Interestingly, bromine is the most commonly found halogen in marine natural products, even though its concentration in seawater is lower than that of chlorine. Of all marine organisms, algae possess the highest abundance of unique biosynthetic pathways for organohalogen production. Seaweeds probably produce halogenated organics as part of a defense system against microorganism infections, herbivore grazing, space competitors, detrimental fouling by different kinds of epiphytes, or excess of self-generated hypochlorite and hydrogen peroxide. The chemotaxonomic value of these compounds has been seriously considered in the past but the geographic and seasonal variation in the chemical composition of algal species has reduced their importance. A significant number of algal halogenated metabolites have exhibited an impressive array of biological properties ranging from antimicrobial to insecticidal activities. Prof. Dr. Vassilios Roussis Guest Editor Submission All papers should be submitted to marinedrugs@mdpi.com with a copy to the Guest Editor. Papers will be published continuously until the deadline and will be listed together at the special issue website. Research articles and review articles are both invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editors for announcement on this website. Submitted papers should not have been published previously, nor be under consideration for publication elsewhere. All papers are refereed through a peer-review process. A guide for authors, sample copies and other relevant information for submitting papers are available on the Instructions for Authors page. Marine Drugs is an international peer-reviewed quarterly journal published by Molecular Diversity Preservation International. Please visit the Instructions for Authors page before submitting a paper. Open Access Article Processing Charges are 1000 CHF per paper. English correction fees (250 CHF) will be added in certain cases (1250 CHF per paper for those papers that require extensive additional formatting and/or English corrections.). Starting 1 January 2010, Article Processing Charges are of 1400 CHF per accepted article for Marine Drugs. http://www.mdpi.com/1660-3397/8/8/2301/ Marine algae produce a cocktail of halogenated metabolites with potential commercial value. Structures exhibited by these compounds go from acyclic entities with a linear chain to complex polycyclic molecules. Their medical and pharmaceutical application has been investigated for a few decades, however other properties, such as antifouling, are not to be discarded. Many compounds were discovered in the last years, although the need for new drugs keeps this field open as many algal species are poorly screened. The ecological role of marine algal halogenated metabolites has somehow been overlooked. This new research field will provide valuable and novel insight into the marine ecosystem dynamics as well as a new approach to comprehending biodiversity. Furthermore, understanding interactions between halogenated compound production by algae and the environment, including anthropogenic or global climate changes, is a challenging target for the coming years. Research of halogenated metabolites has been more focused on macroalgae than on phytoplankton. However, phytoplankton could be a very promising material since it is the base of the marine food chain with quick adaptation to environmental changes, which undoubtedly has consequences on secondary metabolism. This paper reviews recent progress on this field and presents trends on the role of marine algae as producers of halogenated compounds. http://www.mdpi.com/1660-3397/8/8/2301/ Mon, 09 Aug 2010 00:00:00 CEST Marine Drugs 2010-08-09 8 8 Review 2301 2317 1660-3397 Halogenated Compounds from Marine Algae 2010-08-09 doi: 10.3390/md8082301 Maria Teresa Cabrita Carlos Vale Amélia Pilar Rauter http://www.mdpi.com/1660-3397/8/6/1743/ In our continuous interest to study the diversity of halogenated metabolites of Malaysian species of the red algal genus Laurencia, we examined the chemical composition of five populations of unrecorded Laurencia sp. A new brominated diterpene, 10-acetoxyangasiol (1), and four other known metabolites, aplysidiol (2), cupalaurenol (3), 1-methyl-2,3,5-tribromoindole (4), and chamigrane epoxide (5), were isolated and identified. Isolated metabolites exhibited potent antibacterial activities against clinical bacteria, Staphylococcus aureus, Staphylococcus sp., Streptococcus pyogenes, Salmonella sp. and Vibrio cholerae. http://www.mdpi.com/1660-3397/8/6/1743/ Wed, 26 May 2010 00:00:00 CEST Marine Drugs 2010-05-26 8 6 Article 1743 1749 1660-3397 Antibacterial Activities of a New Brominated Diterpene from Borneon Laurencia spp. 2010-05-26 doi: 10.3390/md8061743 Vairappan Ishii Lee Suzuki Zhaoqi http://www.mdpi.com/1660-3397/8/5/1526/ This review discusses the isolation, structural elucidation, and biological activities of halogenated indole alkaloids obtained from marine invertebrates. Meridianins and related compounds (variolins, psammopemmins, and aplicyanins), as well as aplysinopsins and leptoclinidamines, are focused on. A compilation of the 13C-NMR spectral data of these selected natural indole alkaloids is also provided. http://www.mdpi.com/1660-3397/8/5/1526/ Wed, 28 Apr 2010 00:00:00 CEST Marine Drugs 2010-04-28 8 5 Review 1526 1549 1660-3397 Halogenated Indole Alkaloids from Marine Invertebrates 2010-04-28 doi: 10.3390/md8051526 Pauletti Cintra Braguine Filho Silva Cunha Januário http://www.mdpi.com/1660-3397/8/4/988/ Brown algae represent a major component of littoral and sublittoral zones in temperate and subtropical ecosystems. An essential adaptive feature of this independent eukaryotic lineage is the ability to couple oxidative reactions resulting from exposure to sunlight and air with the halogenations of various substrates, thereby addressing various biotic and abiotic stresses i.e., defense against predators, tissue repair, holdfast adhesion, and protection against reactive species generated by oxidative processes. Whereas marine organisms mainly make use of bromine to increase the biological activity of secondary metabolites, some orders of brown algae such as Laminariales have also developed a striking capability to accumulate and to use iodine in physiological adaptations to stress. We review selected aspects of the halogenated metabolism of macrophytic brown algae in the light of the most recent results, which point toward novel functions for iodide accumulation in kelps and the importance of bromination in cell wall modifications and adhesion properties of brown algal propagules. The importance of halogen speciation processes ranges from microbiology to biogeochemistry, through enzymology, cellular biology and ecotoxicology. http://www.mdpi.com/1660-3397/8/4/988/ Tue, 30 Mar 2010 00:00:00 CEST Marine Drugs 2010-03-30 8 4 Review 988 1010 1660-3397 The Halogenated Metabolism of Brown Algae (Phaeophyta), Its Biological Importance and Its Environmental Significance 2010-03-30 doi: 10.3390/md8040988 La Barre Potin Leblanc Delage